Health authorities in the northern province of Hai Duong are testing a batch of Quinvaxem pentavalent vaccine that reportedly killed a baby it was administered to.

The boy of three months old, only identified by his initials D.T.L., received the shot on March 25 together with more than 40 other children, including four who also had negative reactions but have recovered, Nguoi Lao Dong reported.

L. was having his second shot of Quinvaxem, which is given to babies three times every one month from their second month to immunize them against five diseases diphtheria, tetanus, pertussis or whooping cough, hepatitis B, and Hib (Haemophilus influenzae type b).

He suffered a fever, refused breast milk and cried constantly one day after the shot and his parents brought him to the provincial pediatrics hospital, where he died soon after.

Authorities said their test results would be released sometime this week, and the batch would be used again it was found not responsible for the death.

The boy is the ninth death from the pharmaceutical product reported nationwide since last November. The liquid drug, a medicine prequalified by the WHO, has been distributed in Vietnam for free since June 2010 as part of a program run by the Global Alliance for Vaccines and Immunization through the nonprofit organization UNICEF.

The victims suffered from various symptoms including fevers, vomiting and the appearance of bruises all over their bodies.

Local authorities had suspended all the controversial batches for testing, while the Health Ministry and the WHO both later said there were no problems with the vaccine's quality, its distribution, preservation, or administration.

Quinvaxem was introduced globally in 2006 by the Netherlands-based biopharmaceutical company Crucell. Vietnam is using Quinvaxem made in South Korea.

Pharmaceutical companies have pushed the vaccine in low-income countries. It costs around VND77,000 (almost four US dollars) a dose, while new alternatives produced in the US and Belgium cost ten times more.